Turbine dry powder inhaler

ABSTRACT

A turbine powered inhaler has a propeller mounted on a turbine shaft within an aerosolizing chamber. An air pathway extends from an inlet, through the turbine to the aerosolizing chamber, and out through a mouth piece. Upon inhalation by a patient, air flowing through the air path rapidly spins up the turbine which directly drives the propeller within the aerosolizing chamber. Air and drug particles are mixed and de-agglomerated in the aerosolizing chamber via the spinning propeller, without the need for a motor and batteries.

BACKGROUND OF THE INVENTION

The field of the invention is inhalers for delivering dry powderpharmaceuticals to the lungs.

Inhalers have long been used to deliver pharmaceuticals into a patient'slungs. Dry powder inhalers provide a mixture of a dry powderpharmaceutical and air to the patient. The air/pharmaceutical powdermixture is delivered via the patient inhaling from a mouthpiece on theinhaler. The Spiros® inhaler, described in U.S. Pat. Nos. 5,327,883 and5,577,497, and U.S. Pat. Nos. 5,921,237 and 6,116,238, all incorporatedherein by reference, hold great potential for improved delivery of drypowder pharmaceuticals to the lungs. These inhalers use a small electricmotor which spins a propeller within an aerosolizing chamber. Thespinning propeller efficiently mixes the air and powder pharmaceuticalin the aerosolizing chamber, and also helps to separate the active drugparticles from inactive carrier particles, increasing the respirablefraction of the pharmaceutical composition. However, the motor,batteries, switch, indicator lights, and related circuitry in theseinhalers increase their manufacturing cost and complexity. Consequently,although these types of inhalers are greatly improved over priorinhalers and have performed very well in clinical tests, there remains aneed for a dry powder inhaler having good efficiency yet with a simplerand less costly design.

Accordingly, it is an objection of the invention to provide a dry powderinhaler having the advantages of a propeller spinning within anaerosolizing chamber but with a simpler and less costly configurationthan known inhalers.

SUMMARY OF THE INVENTION

To these ends, a dry powder inhaler has a turbine adjacent to anaerosolizing chamber. A turbine shaft extends out of the turbine andinto the aerosolizing chamber. A propeller is mounted on the turbineshaft in the aerosolizing chamber. When the patient inhales, the turbinerapidly accelerates to a high rotational speed, driving the propellerwithin the aerosolizing chamber. As a result, the advantages provided bythe propeller spinning within the aerosolizing chamber are largelyrealized, without the need for a motor and batteries, or other powersource. Manufacturing cost and complexity are reduced. As the propellerand turbine are powered by the patient's inhalation, battery life is nolonger a factor in inhaler operation, and the turbine inhaler may beused indefinitely, within the mechanical wear limits of the components.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects features and advantages will become apparent to thoseskilled in the art from the following drawings and descriptions. Thedrawings, which show a single embodiment, are provided for purposes ofillustration only, and are not intended as a limitation of the forms ofthe invention.

In the drawings, wherein the same reference number denotes the sameelement, throughout the several views:

FIG. 1 is a perspective view of the present inhaler;

FIG. 2 is a plan view thereof;

FIG. 3 is an exploded perspective view thereof;

FIG. 4 is a perspective view of the inhaler shown in FIG. 3;

FIG. 5 is a perspective view thereof, also showing internal turbinedetails;

FIG. 6 is a schematic view showing air flow through the inhaler; and

FIG. 7 is an enlarged view of details shown in FIG. 6.

DETAILED DESCRIPTION OF THE DRAWINGS

Turning now in detail to the drawings, as shown in FIG. 1, an inhaler 10has a mouthpiece 14 attached to a body 12. A mouth piece cover 16 isattached to the mouth piece 14 via a hinge 15. The mouth piece cover 16can be pivoted open or removed during inhalation, or for cleaning.

Referring now to FIGS. 2 and 3, a blister disk 18 having a transparentcover 20 is mounted over a disk plate 22 attached to the body 12. Anaerosolizing chamber 24 is formed in the front wall of the body 12.

A turbine 30 supported on the underside of the disk plate 22 has aturbine shaft 46 extending forwardly into the aerosolizing chamber 24. Apropeller 26 is mounted on the forward end of the turbine shaft 46 inthe aerosolizing chamber 24. A lower housing 32 encloses the bottomsection of the disk plate 22. A plunger 34 extends through the lowerhousing 32, for opening blisters on the blister disk 18. The body 12 andlower housing 32 form an inhaler housing 11.

The design details and operation of the inhaler 10 are similar to theinhalers described in U.S. Pat. Nos. 5,622,166, and U.S. Pat. Nos.5,921,237 and 6,116,238, incorporated herein by reference. However, theinhaler 10 has no motor, batteries, switch or circuitry. Rather, thespinning propeller 26 is powered purely by the turbine 30.

Referring to FIGS. 4-7, the turbine 30 has a cylindrical turbine housing40. A stator 52 joined to the turbine housing 40 near the turbine inlet42. A turbine outlet 44 is preferably positioned on one side of thecylindrical turbine housing 40, at the outlet end 45 of the turbine 30.The turbine shaft 46 is rotatably supported within the turbine housing40 via a bushing 48 near the outlet end 45, and via a needle bearing 50near the inlet end 42. A rotor 54 having pitched turbine blades 56 isattached and centered on the turbine shaft 46 adjacent to the stator 52.

Turning to FIGS. 6 and 7, and air inlet path 36 extends from the outsideenvironment into the inhaler 10, and to the inlet end 44 of the turbine30. A turbine outlet duct or path 60 runs from the turbine outlet 44 toa staging chamber 62 in the body 12 of the inhaler 10. An aerosolizingchamber duct 64 extends from the staging chamber 62 to the aerosolizingchamber 24. A chamber wall 15 in the mouth piece 14, as shown in FIG. 3forms the front wall of the aerosolizing chamber 24, when the mouthpiece 14 is attached on to the body 12. Openings in the chamber wall 15allow the drug/air mixture to flow from the aerosolizing chamber 24through the mouth piece 14 to the patient.

In use, a dose of dry powered drug is delivered into the staging chamber62 from the blister disk 18, as described in U.S. Pat. Nos. 5,622,166and U.S. Pat. Nos. 5,921,237, and 6,116,238. The patient places the lipsover the mouth piece 14 and inhales. Upon inhalation, ambient air flowsthrough the inlet air path 36 to the inlet end 42 of the turbine 30. Theair flowing at right angles to the plane of the rotor 54 rapidly spinsup the rotor and turbine shaft 46, simultaneously rapidly spinning upthe propeller 26 which is directly mounted on to the front end of theturbine shaft 46. The rotor blades are pitched so that the air flowthrough the turbine, parallel to the axis of the turbine shaft, exertstorque, causing the rotor to spin. Air flows out of the turbine outlet44 to the staging chamber 42. Dry powder pharmaceutical particles areentrained in the air flow and carried through the aerosolizing chamberduct 64 into the aerosolizing chamber 24. The particles arede-agglomerated and mixed with air in the aerosolizing chamber 24. Theair and particles pass out of the aerosolizing chamber 24 throughopenings in the chamber walls 15 and into the patient's mouth, throat,and lungs.

Preferably, the turbine is designed to that the turbine shaft will spinat from 5,000-15,000 rpm with an inspiration flow rate of 20-40 litersper minute. Most preferably, the turbine 30 is designed so that it spinsup to 10,000 rpm or greater, within 100 milliseconds, with aninspiration flow rate of about 30 liters per minute. The stator 52 mayhave fixed vanes to better direct air flow to the rotor 54. Additionalrotors 54 may optionally be added to the shaft 46.

The air flow through the inhaler 10 is substantially sealed, so that allair inhaled by the patient passes through the inlet air path 36, theturbine 30, the turbine outlet duct 60, the aerosolizing chamber duct64, the aerosolizing chamber 24, and out through the mouth piece 14. Forembodiments not having a separate dump chamber, air flowing out of theturbine may go directly into the aerosolizing chamber. Alternatively, afraction of the total airflow into the patients lungs may be eitherinletted or channeled through ducts in the mouthpiece or inhaler to helpbeneficially entrain, mix, or guide the particle laden air mixture.

The turbine 30 may advantageously be provided as a separate subassemblyinstalled into the inhaler 10 during manufacture. As a result, variousother components of the inhaler, not requiring the precision tolerancesnecessary in the turbine, can be manufactured and assembled separately.The turbine is compact, preferably having a housing diameter of 1-2centimeters.

As shown in FIGS. 6 and 7, the dry powder does not flow through theturbine 30. Rather, the turbine 30 is upstream from the powder. Theturbine therefore avoids clogging, friction, or bearing failure frompowder particles, as the turbine is upstream of the powder. Although theturbine 30 uses the same air flow which entrains the powder, nobalancing of air flow paths is required, and no coordination or timingof the spin-up of the turbine is needed, as the turbine automaticallyspins up upon inhalation.

The inhaler 10 consequently provides advantages of a motorized inhaler,without the need for a motor or batteries. If electronics are desired toprovide an interface with the patient (for example, for dose counting,etc.) then very small batteries may be included to provide the typicallow power requirements for such circuitry.

It may be desirable to allow the turbine enough time to reach a minimumacceptable rotary speed to de-agglomerate the drug, before the drug haspassed through and out of the aerosolization chamber. One technique forthis is to delay the introduction of the pharmaceutical mixture into theaerosolization chamber by sizing the length and diameter of the air pathleading to the staging chamber. This allows the turbine time to reachthe desired minimum rotational speed. As one example, if the outlet duct60 is 1 cm diameter and 2.5 cm long, during the initial period ofinhalation, at a flow rate of 5 liters per minute, the air takes 24 msto reach the aerosolizing chamber. During that interval the turbine hasaccelerated up to a sufficient minimum speed.

Alternatively the inhaler may be inverted so that the air flowingthrough the turbine and hence ‘over’ the open well containing theblister has to reach a high enough velocity (i.e., 23 liters per minute,depending on how the local geometry is configured) to ‘lift’ theparticles out of the blister well due to Bemoull's principal, ratherthan the particles just falling out of the well due to gravity evenbefore the inhalation has begun. This could act as a passive method forregulating when the drug is introduced to the system based on theairflow rate.

In another embodiment intended to have the drug particles exposed to thespinning propeller in the aerosolization chamber is to place therestrictor holes, or outlet holes, near the center of the chamber ratherthan at the periphery. This would act like a centrifugal size filter,i.e. the larger particles would be forced to the periphery where themost aggressive de-agglomeration takes place until they are small enoughto reach the more centralized outlet holes.

Thus, a novel inhaler has been shown and described. Various changes andmodifications may, of course, be made, without departing from the spiritand scope of the invention. The invention, therefore, should not berestricted, except by the following claims, and their equivalents.

What is claimed is:
 1. An inhaler comprising: a housing; an aerosolizingchamber within the housing; a propeller within the aerosolizing chamber;a turbine adjacent to the aerosolizing chamber, the turbine having aninlet side and an outlet side; a turbine shaft extending out of theturbine and into the aerosolizing chamber, with the propeller linked tothe turbine shaft; a first air pathway extending from an air inlet inthe housing to an inlet side of the turbine; and a second air pathwayextending from the outlet side of the turbine to the aerosolizingchamber.
 2. The inhaler of claim 1 further comprising a stator on theturbine and a rotor on the turbine shaft.
 3. The inhaler of claim 1wherein the turbine outlet is oriented at an angle to the turbine inlet.4. The inhaler of claim 1 wherein the turbine is configured to spin theturbine shaft at from 5000 to 15000 rpm with a flow rate of 20-40liters/minute of air flowing through the turbine.
 5. The inhaler ofclaim 1 further comprising a staging chamber in the second air pathway,between the turbine outlet and the aerosolizing chamber.
 6. The inhalerof claim 1 further comprising a rotor attached to the turbine shaft,with the turbine shaft and rotor having an axis of rotation parallel tothe direction of air flow through the turbine.
 7. The inhaler of claim 6where the second air pathway is configured so that air flowing throughit lifts drug particles out of the staging chamber, and entrains theparticles in the flowing air.
 8. The inhaler of claim 1 with theaerosolizing chamber having outlet holes near the center of the chamber,for filtering particles by size.
 9. The inhaler of claim 1 furthercomprising a mouthpiece on the inhaler connected to the aerosolizingchamber, and with the first and second air pathways, the aerosolizingchamber, and the mouthpiece forming a substantially sealed air flow paththrough the inhaler.
 10. The inhaler of claim 1 where the second airpathways are configured to delay introduction of a dry powder into theaerosolizing chamber until after the propeller is spun up to a minimumspeed.
 11. The inhaler of claim 1 where the propeller has two blades.12. The inhaler of claim 1 where the propeller is mounted on the turbineshaft.
 13. The inhaler of claim 1 where the turbine shaft extendssubstantially from the turbine inlet to the turbine outlet.
 14. Theinhaler of claim 1 with the turbine having rotor blades oriented so thatair flow from the turbine inlet exerts torque on the turbine shaft. 15.An inhaler comprising: a housing; an inlet in the housing; anaerosolizing chamber within the housing; a mouthpiece on the housingconnecting with the aerosolizing chamber; a propeller in theaerosolizing chamber; a turbine within the housing and outside of theaerosolizing flow and coupled to the propeller; and an air pathextending from the inlet, through the turbine, into the aerosolizingchamber, and out to the mouthpiece.
 16. A method of providing a dose ofan inhaled pharmaceutical to a patient, comprising the steps of:providing a pharmaceutical powder into an aerosolizing chamber in aninhaler; drawing air through a turbine as the patient inhales, therebyspinning a propeller, attached to the turbine, in the aerosolizingchamber; mixing air and the pharmaceutical powder in the aerosolizingchamber via the spinning propeller.
 17. The method of claim 16 whereinthe air is drawn through the turbine in a direction perpendicular to theplane of a rotor in the turbine, passes through the aerosolizingchamber, and is then inhaled by the patient.
 18. The method of claim 16wherein the pharmaceutical powder is mixed with air flowing out of theturbine, to avoid having the powder contact the turbine.
 19. The methodof claim 16 where the turbine spins up to at least 10,000 rpm within a100 millisecond interval.
 20. The method of claim 16 where the turbinespins at from 5,000-15,000 rpm with the patient inhaling at 20-40 litersper minute.
 21. The method of claim 16 further including the step ofconducting all of the air drawn through the turbine into theaerosolizing chamber.
 22. The method of claim 16 further comprising thestep of delaying the providing of the pharmaceutical powder into theaerosolizing chamber by a delay interval, to allow the propeller to spinup to a minimum acceptable speed, before the powder is provided into theaerosolizing chamber.